I had those little hanging metal bases made so you can hang your magnetic knife vases anywhere, and not only on your fridge! 

Measures approximately 18cmx6cm and can be hung on the wall with two nails or screws.

Here you are buying the metal base alone, you can also buy a set of 3 knife vases with metallic hanging base, or a set of 4 knife vases with metallic hanging base. The design of those sets is subject to availability.